Internal combustion engine



March 8, 1932. A. w. ARNOLD 1,848,597

INTERNAL COMBUSTION ENGINE Filed June 28, 1929 3 Sheets-Sheet l March 8, 1932.

A. w. ARNOLD INTERNAL COMBUSTION ENGINE Filed June 28, 1929 3 Sheets-Sheet 2 March 8, 1932. w, ARNOLD 1,848,597

INTERNAL COMBUSTION ENGINE Filed June 28, 1929 3 Sheets-Sheet 5 lllflllllllill Fig. 2 is a transverse sectional view through one of the cylinders showing the parts in their intake positions;

Fig. 3 is a similar view showing the parts in their positions for compression;

Fig. 4 shows a firing position;

Fig. 5 illustrates the operation of the parts s q for power;

Fig. 6 shows the exhausting position; and

Fig. 7 isa detailed'perspective view of a portion of the operating mechanism for the movable head.

The invention is illustrated in connection with a four-cycle internal combustion engine of the usual type, which is provided with a crank-case 1 to which the cylinders 2 are connected. J ournaled in the crank-case 1 is the usual crank-shaft 3 having the cranks 4 thereon, and with which cranks the connecting-rods 5 are connected and extend to the power pistons 6 disposed in the cylinders 2 for operation therein.

Disposed at one side of the crank-shaft 3 is the usual cam-shaft 7 for operating the intake and exhaust fuel valves 8 and 9, which communicate through the passage-way 10 Y with each of the cylinders 2. A spark-plug 11 may be disposed in this passage-way-or in communicating relation with each of the cylinders in order to cause a firing of the explosive mixture at properly timed intervals for operation of the power pistons.

Mounted in the upper or outer end of each of the cylinders 2 is a movable head 12, which has limited movement in the cylinder and closes the upper or outer end of the cylinder. This movable head 12 has a cross-head 13 connected therewith, carrying a roller or bearing 14 which extends into operative engagement with a cam 15 fixed to a cam-shaft 16 disposed immediately above the cylinders 2.

This cam-shaft 16 is driven as shown in Fig. 1 by a chain or flexible connecting member 17 from the crank-shaft 3, so as to be operated in properly timed relation to the crank-shaft. The operative speeds of these may be regulated as found desirable.

The cross-head 13 connected with each of the movable heads 12 is provided with a normally in operative relation transverse opening 18 through which a sup orti'ng-plate 19 extends as shown clearly in ig. 7, having its opposite ends fixed to the outer end of the cylinder 2. A spring19' is interposed between this supporting-plate 19 and the upper end of the opening 18 so as to tend to hold the cross-head 13 against the surface of thecam 15.

It will be noted that the are a of each of the cams 15 is concentric with the cam-shaft 16 and extends throughout approximately slightly less than half of the circumference of the cam. The are or portion a is connected by means of the spiral arc-shaped portion 6 of approximately one-fourth of the circumference with an arc-shaped ortion c likewise concentric with the cam-s aft 16 but of a shorter radius than the portion a, and this portion 0 extends throughout approximately one-fourth of the circumference of the cam 15 and is connected at its opposite end with the portion a through an abrupt curved portion d.

Modifications may be made in the forms of cams used, but the one illustrated and described has been found suitable and convenient for actuating the movable head 12 in proper timed relation with the actuation of the power piston 6.

In the operation of the engine, it will be noted that Fig. 2 illustrates the power piston and movable head in their intake positions with the intake valve 8 open, admitting a charge of gaseous fuel into the cylinder 2, and with the power piston 6 in its extreme lower position and the movable head 12 after it has been just returned to its uppermost position. Fig. 3 shows the intake valve having closed while the power piston 6 has been moved to its uppermost position and the movable head 12 remaining in its uppermost position effectively controls the gaseous charges of fuel which have been drawn into the cyhnder and the compression chamber 20, being that portion of the cylinder 2 between the power-piston 6 and the movable head 12.

Heretofore, as is well known, it has been the practice to so regulate the timing that the compressed charge of fuel will be ignited at or slightly prior to the time when the piston is on dead center, which is at its extreme uppermost position, being the position illustratcd in Fig. 3. It is evident that the maximum benefit is not derived from the explosion as if it occurred after the piston had moved beyond dead center, thus obtaining a more advantageous angle of leverage. Heretofore, this has been accomplished by retarding the spark which delays the spark until after the piston has assed beyond dead center and the explosion then occurs on the downward movement of the piston, thus giving better leverage on the crank-shaft. However, the fact that the piston has started downward even to a very slight extent, re-

duccs the maximum compression of the gasethe time of the explosion by enlarging that combustion-chamber. This reduces the power of the explosion. In other words, the operator has sacrificed power to obtain greater leverage on the crank-shaft in order to obtain smoother running of the engine.

With my invention, it will be noted that the firing position illustrated in Fig. 4 is a position in which the crank 4 of the crankshaft has passed to a point approximately thirty degrees beyond dead-center at the time of the explosion. In this way the power-piston 6 is lowered, but by reason of the abrupt piston,

Patented Mar. 8, 1932 ALBERT W. ARNOLD, 01 CHARLOTTE, NORTH CHARLOTTE, NORTH CAROLINA.

VICTOR EARL IRONS, OF

CAROLINA, ASSIGNOR-OF ONE-HALF TO INTERNAL COMBUSTION ENGINE Application filed June 28,

My invention relates to an improvement in internal combustion engines.

, The object of this invention is to provide for maintaining the maximum pressure of the gaseous charges constant, long enough to permit the explosion to occur with the gaseous charges prolonged and in contact with the hot Walls of the combustion'chamber until the 0 center. 1

It is a well-known fact that in internal combustion engines the gaseous charges are ordinarily ignited at, or slightly prior to, the time when the piston is on dead-center. It is evident then that the maximum benefit to be derived from the explosion is not as great as it would be were the piston at a more advantageous angle of leverage. Every motorist is aware that when his motor begins to labor up a hill, his whole car is subject to vibrations, and if continued, the motor begins to knock. This is due to the fact that the fly-wheel is now turning so slowly that the whole benefit of the explosion is being exerted directly against the dead-center position of the piston and crank. To eliminate this knock, the driver retards his spark, which results in a smooth running motor with less vibration, but with tremendously diminished ower. This smooth running is due to the Fact that the charge is now ignited when the piston has started on its downward stroke, and hence has passed the dead center point, thus giving a better leverage point on the-crank.

But the fact that the piston has started downward ever so little has reduced the maximum compression of the gaseous charges at the time of explosion by enlarging the combustion-chamber. This reduces the power of the ex losion. In other words, the driver has sacrificed power in order to obtain greater leverage on his crank, resulting in smooth or running and elimination of knocks.

The purpose of my invention, therefore, is to glain the advantages of the retarded spark wit out sacrificing the power of the advance spark. 'To do thls, I simply fit the head of my engine with a slightly movable auxiliary which moves in the same direction piston has passed beyond dead on dead center.

1929. Serial No. 374,564.

and at the same rate of speed as the power piston during the first part of its power stroke, and until it is well past dead-center. In other words, I simply retain the size of the combustion-chamber so that it has the same cubic content after the piston has started and continued for some distance downward that it did when the power piston was at its extreme uppermost position. By retaining the same compression existing when the piston was-on its extreme uppermost position until the piston has traveled considerably past dead center, I am able to ignite the gaseous charges while they are still at their maximum pressure, and yet when the effect of this explosion is exerted against the crank at a point of greater leverage.

Thus I obtain the smooth running qualities and absence of knocks ordinarily obtained by a retarded spark, and at the same time get the.

full power from the explosion under maximum compression that is ordinarily obtained under advanced spark. At the same time greater power is received because my engine permits the piston to exert the same power at a more advantageous angle of leverage than is ordinarily exerted against the piston when Greater power is also obtained because the gaseous charges will be prolonged in contact with the hot walls of the combustion chamber under that maximum pressure for a longer time than theinstantaneous moment when the piston of the ordi nary engine is at its on dead center. This is becausethe power piston and the auxiliarypiston o r movable head after reaching the point giving greatest compression maintain this pressure by traveling together in the same direction and at the same rate of speed until the piston has traveled at least a part of its downward stroke. his prolonging of the gaseous charges against the hot walls of the combustion chamber without diminishing their pressure, results in a more volatile and powergiving mixture.

In the accompanying drawings:

Fig. 1 is a longitudinal sectional view illustrating the invention as applied to a fourcycle internal combustion engine;

uppermost extremity or cam portion (1, the movable head 12 has been lowered to the same extent, and at the same speed, as the initial downward movement of the ower-piston 6, thereby maintaining the com ustion chamber 20 of approximately the same size 'and capacity, effectively maintaining but not increasing the size of that combustion-chamber and the compression of the gaseous charges maintained in it. In other words, by reason of the downward movement of the movable head 12 with, and at, the same speed as the initial downward movement of the power piston 6, the maximum compression of the gaseous charges in the combustion chamber obtained when the power piston was moved to its extreme uppermost position is maintained and retained until after the power piston has moved a substantial distance beyond dead center, so as to permit of the timing of the spark to cause the explosion to occur at a point of greater leverage on the crank-shaft, but

' without reducing the power or lessening the compression of the gaseous charges in the combustion chamber. v

The downward movement of the power piston 6 after the explosion, applies that power to the crank-shaft 3, that position being illustrated in Fig.5, and the position of the movable head 12 remains as in Fig. 4 in its lowermost position. Upon the upward movement of the power piston 6, as shown in Fig. 6, the exhaust-valve 9 is opened to cause the burnt gases to be forced from the cylinder or the combustion-chamber, and the-movable head 12 remains in its lowermost position with its lower face approximately in alignment with the upper e ge of the chamber 10 to facilitate the removal or forcin out of the burnt gases. Upon the downward movement of the power iston 6 again, the exhaust-valve 9 is closed valve 8 opened to admit a new char of fuelas shown in Fig. 2, and at this time the movable head-12 is caused to be moved to its uppermost position, this movement facilitating the drawing in of the fuel for a re tition of the operation of the engine as a ove described. I v 1 In this way, and by reason of my invention the full compression is maintained and retamed until the power-piston has passed a substantial distance beyond dead center, thus prolonging the period of contact of the fully compressed gases with the hot firing chamber walls, and thereby facilitating more complete and rfect combustion, but without reducing t e compression of the gaseous charges.

I claim:

In an internal combustion engine, the combination of a cylinder having an opening in the outer end thereof, a power piston within the cylinder, a movable head in the cylinder, a cross-head connected with the movable and the intake;

. resilient means interposed between said support and the cross-head, and a cam acting-on the cross-head opposed to said resilient means.

In testimony whereof I afiix my signature.

ALBERT W. ARNOLD. 

